This invention relates to a tracking radar system having: an antenna with at least one direction of maximum gain, hereinafter called the boresight; means for producing signals indicating an angular difference between the direction of a target and the boresight; and means for changing the boresight in response to the said signals so as to tend to reduce that difference.
Radar systems as described above suffer from a problem in that the aforementioned signal may sometimes indicate short term changes in the angular position of the target, which changes do not actually occur. This is because of (a) target "glint", i.e. changes in the reflection properties of the target as it changes in attitude; (b) "multipath" which is the existance of two paths for the transmission of signals to the target and/or reflection of signals from the target (this can be caused for example by reflection off the sea surface); and (c) thermal noise generated within the receiving circuit.